package com.zy.acs.manager.core.scheduler;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.zy.acs.manager.core.service.GuaranteeRuntimeService;
import com.zy.acs.manager.manager.entity.Guarantee;
import com.zy.acs.manager.manager.enums.StatusType;
import com.zy.acs.manager.manager.service.GuaranteeService;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.scheduling.support.CronExpression;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;

@Slf4j
//@Component
public class GuaranteeScheduler {

    private final GuaranteeService guaranteeService;
    private final GuaranteeRuntimeService guaranteeRuntimeService;

    @Value("${guarantee.scheduler.enabled:true}")
    private boolean enabled;
    @Value("${guarantee.scheduler.default-lead-minutes:60}")
    private int defaultLeadMinutes;
    @Value("${guarantee.scheduler.lock-duration-minutes:5}")
    private int lockDurationMinutes;
    @Value("${guarantee.scheduler.window-duration-minutes:10}")
    private int windowDurationMinutes;

    private final Map<Long, PlanRuntimeState> runtimeStates = new ConcurrentHashMap<>();

    public GuaranteeScheduler(GuaranteeService guaranteeService,
                              GuaranteeRuntimeService guaranteeRuntimeService) {
        this.guaranteeService = guaranteeService;
        this.guaranteeRuntimeService = guaranteeRuntimeService;
    }

    @Scheduled(cron = "0/15 * * * * ?")
    public void drive() {
        if (!enabled) {
            return;
        }
        List<Guarantee> plans = guaranteeService.list(new LambdaQueryWrapper<Guarantee>()
                .eq(Guarantee::getStatus, StatusType.ENABLE.val));
        syncCache(plans);
        LocalDateTime now = LocalDateTime.now();
        for (Guarantee plan : plans) {
            try {
                processPlan(plan, now);
            } catch (Exception ex) {
                log.error("GuaranteeScheduler failed for plan {}", plan.getName(), ex);
            }
        }
    }

    private void processPlan(Guarantee plan, LocalDateTime now) {
        PlanRuntimeState state = runtimeStates.computeIfAbsent(plan.getId(), id -> new PlanRuntimeState());
        if (state.getTargetTime() == null || now.isAfter(state.getWindowEnd())) {
            LocalDateTime next = computeNext(plan, now);
            if (next == null) {
                runtimeStates.remove(plan.getId());
                return;
            }
            state.init(plan, next, resolveLeadMinutes(plan));
        }
        if (now.isBefore(state.getPrepareStart())) {
            state.setPhase(Phase.IDLE);
            return;
        }
        if (now.isBefore(state.getLockStart())) {
            state.transition(Phase.PREPARING, () -> guaranteeRuntimeService.prepare(plan, state.getTargetTime()));
            return;
        }
        if (now.isBefore(state.getTargetTime())) {
            state.transition(Phase.LOCKING, () -> guaranteeRuntimeService.lock(plan, state.getTargetTime()));
            return;
        }
        if (now.isBefore(state.getWindowEnd())) {
            state.transition(Phase.WINDOW, () -> guaranteeRuntimeService.checkWindow(plan, state.getTargetTime()));
            guaranteeRuntimeService.checkWindow(plan, state.getTargetTime());
            return;
        }
        if (state.getPhase() != Phase.FINISHED) {
            state.transition(Phase.FINISHED, () -> guaranteeRuntimeService.finish(plan, state.getTargetTime()));
        }
        LocalDateTime next = computeNext(plan, state.getWindowEnd().plusSeconds(1));
        if (next == null) {
            runtimeStates.remove(plan.getId());
            return;
        }
        state.init(plan, next, resolveLeadMinutes(plan));
    }

    private void syncCache(List<Guarantee> plans) {
        Set<Long> activeIds = plans.stream().map(Guarantee::getId).collect(Collectors.toSet());
        runtimeStates.keySet().removeIf(id -> !activeIds.contains(id));
    }

    private int resolveLeadMinutes(Guarantee plan) {
        return Math.max(1, plan.getLeadTime() == null ? defaultLeadMinutes : plan.getLeadTime());
    }

    private LocalDateTime computeNext(Guarantee plan, LocalDateTime reference) {
        String cronExpr = plan.getCronExpr();
        if (cronExpr == null || cronExpr.trim().isEmpty()) {
            return null;
        }
        try {
            CronExpression cron = CronExpression.parse(cronExpr);
            LocalDateTime base = reference == null ? LocalDateTime.now() : reference;
            LocalDateTime next = cron.next(base);
            if (next == null && !base.equals(LocalDateTime.now())) {
                next = cron.next(LocalDateTime.now());
            }
            return next;
        } catch (IllegalArgumentException ex) {
            log.error("Guarantee[{}] invalid cron {} ", plan.getName(), cronExpr, ex);
            return null;
        }
    }

    private enum Phase {
        IDLE,
        PREPARING,
        LOCKING,
        WINDOW,
        FINISHED
    }

    @Data
    private class PlanRuntimeState {
        private LocalDateTime targetTime;
        private LocalDateTime prepareStart;
        private LocalDateTime lockStart;
        private LocalDateTime windowEnd;
        private Phase phase = Phase.IDLE;

        private void init(Guarantee plan, LocalDateTime target, int leadMinutes) {
            this.targetTime = target;
            this.prepareStart = target.minusMinutes(Math.max(1, leadMinutes));
            int lockMinutes = Math.min(lockDurationMinutes, leadMinutes);
            this.lockStart = target.minusMinutes(Math.max(1, lockMinutes));
            this.windowEnd = target.plusMinutes(Math.max(1, windowDurationMinutes));
            this.phase = Phase.IDLE;
            log.info("Guarantee[{}] next target {} prepare@{} lock@{} windowEnd@{}",
                    plan.getName(), targetTime, prepareStart, lockStart, windowEnd);
        }

        private void transition(Phase targetPhase, Runnable callback) {
            if (this.phase.ordinal() >= targetPhase.ordinal()) {
                return;
            }
            callback.run();
            this.phase = targetPhase;
        }
    }
}